How much radiation is the chemotherapy worth in advanced head and neck cancer?

Accelerated Radiotherapy Alone Versus Chemoradiation in Locally Advanced Carcinoma Cervix: Long-Term Outcomes

Introduction Chemoradiation (CRT) is the standard of care for the treatment of carcinoma cervix, more benefits of CRT are seen in the early stage as compared to a locally advanced stage. Altered fractionation such as accelerated radiotherapy (ART) in locally advanced carcinoma cervix has not been explored much. Here, we have reported the long-term outcome of ART in comparison to conventional CRT in locally advanced cervical cancer patients. Methods From September 2011 to January 2014, 191 patients with locally advanced squamous cell carcinoma of the uterine cervix, FIGO stage IIB - IIIB were included in this study. They were randomized into two arms: the CRT arm (95 patients) versus the ART arm (96 patients). During external beam radiotherapy (EBRT), the patients in the CRT arm received conventional radiotherapy 50 Gy/25 fractions, 2 Gy/fraction, 5 fractions/week with cisplatin 40 mg/m2/week while patients in the ART arm received 50 Gy/25 fractions, 2 Gy/fraction, 6 fractions per week (Monday to Saturday) radiation alone. This was followed by three insertions of 6.5 Gy per fraction of high dose rate (HDR) brachytherapy at one-week intervals in both arms to keep the total treatment time 50 days in the CRT arm versus 45 days in the ART arm. Results The median follow-up of the study population was 57 months (range: 4-108 months). The patients with no residual disease (NRD) after EBRT and complete response (CR) at first follow-up were statistically less in the ART arm as compared to the CRT arm (30.2% versus 53.7% and 42.7% versus 63.2%; p = 0.006 and p = 0.024, respectively). However, there was no statistical difference in response at six months. High-grade acute toxicities hematological (9.5%) and gastrointestinal (15.8%) were more prevalent in the CRT arm in comparison to the ART arm, with no statistical significance (p>0.05) and Grade 1/2 genitourinary toxicity was significantly higher in the CRT arm. Late toxicities in both groups were equivalent. Recurrence, distant type of recurrence, and time to recurrence were similar in both groups. Five-year rates of overall survival (OS) and disease-free survival (DFS) were 51.2% versus 37.2% (p = 0.087) and 57.1% versus 46.3% (p = 0.223) in the CRT arm versus ART arm, respectively. Conclusion ART is a compelling alternative to concurrent chemoradiotherapy for locally advanced cervical cancer, particularly in patients with significant comorbidities, elderly women, and those in higher stages where concurrent chemotherapy's efficacy diminishes. It should be strongly considered when chemotherapy is contraindicated.

Are we ready for deintensification in human papillomavirus-positive oropharyngeal carcinomas?

PURPOSE OF REVIEW

Excellent outcomes following contemporary treatment of human papillomavirus (HPV)-positive oropharyngeal carcinoma (HPV+ OPC) have prompted the exploration of deintensification approaches to minimize treatment-related toxicities. This review describes the landscape of deintensification to date (up to November 2022).

RECENT FINDINGS

Although several deintensification trials have been published, none are practice changing. Three phase III randomized-controlled trials studying cetuximab and radiation therapy vs. standard chemoradiotherapy all showed inferior outcomes. Although some phase II trials reported favourable outcomes, they are often single-arm trials without an adequate control arm, thereby limiting the ability to modify practice.

SUMMARY

Substantial effort has been expended to explore deintensification options for selected HPV+ OPC patients aiming to avoid unnecessary toxicity. Strategies have included replacing cisplatin with cetuximab, reduced chemotherapy or radiotherapy intensity, reduction of radiotherapy volumes and risk stratification after trans-oral surgery or following induction chemotherapy. Challenges remain in the current deintensification landscape, including identifying the most suitable candidates along with a choice of most appropriate deintensification strategies. Promising selection criteria included either static baseline features or kinetic characteristics of clinical-biological parameters. Practice-changing trials remain elusive, and the search continues to attempt optimization of the therapeutic ratio for these patients.

Osteonecrosis of the jaw in primary dental care: Recognition and referral

Osteoradionecrosis (ORN) and medication-related osteonecrosis of the jaw (MRONJ) are uncommon conditions, however when present they have a significant impact on a patient's quality of life and are notoriously difficult to treat. With medical advances resulting in improved survival rates and increased life expectancy, it is likely that general dental practitioners (GDPs) will more frequently be involved in the oral health management of patients at risk of both ORN and MRONJ. Though management of both diseases is beyond the scope of primary care dentistry, the GDP still has a key role in the patient's overall care. It is therefore important to have a good understanding of these conditions and their consequences for dental treatment in order to provide adequate patient support. Management requires a multidisciplinary approach to treatment and as part of this GDPs are integral in prevention, early recognition and maintenance of oral health following diagnosis. This article aims to refresh the reader's knowledge regarding MRONJ and ORN and support the GDP in managing this patient group.

Contemporary management of the neck in nasopharyngeal carcinoma

Up to 85% of the patients with nasopharyngeal carcinoma present with regional nodal metastasis. Although excellent nodal control is achieved with radiotherapy, a thorough understanding of the current TNM staging criteria and pattern of nodal spread is essential to optimize target delineation and minimize unnecessary irradiation to adjacent normal tissue. Selective nodal irradiation with sparing of the lower neck and submandibular region according to individual nodal risk is now emerging as the preferred treatment option. There has also been continual refinement in staging classification by incorporating relevant adverse nodal features. As for the uncommon occurrence of recurrent nodal metastasis after radiotherapy, surgery remains the standard of care.

The impact of intensity-modulated radiation treatment on dento-alveolar microvasculature in pharyngeal cancer implant patients

OBJECTIVES

Dental rehabilitation post-radiotherapy often requires the consideration of dental implants. However, these are tentatively prescribed due to the concern of hypovascularisation and possible osteoradionecrosis. Hence, the current study assessed the microvasculature of the dento-alveolar bone at implant sites taking into consideration the exact radiotherapy dose received to the region.

MATERIALS AND METHODS

Bone cores were taken from nine patients during implant treatment and compared to nine control patients. Specimens were stained using CD31 and digitalised using a high-resolution scanner for qualitative and quantitative assessment of the microvasculature. Monaco^® treatment planning system was used to volume the implant site providing mean dose (D_mean ) and maximum dose (D_max ).

RESULTS

A total of 23 bone cores were retrieved for analysis. The cohort had a D_mean of 38.4 Gy (59.6-24.3 Gy). Qualitative analysis identified a clear reduction in the miniscule terminal capillaries and high incidence of obliterated lumens with increasing radiotherapy. Microvasculature density of irradiated patients was markedly reduced (P = .0034) compared to the control group with an inverse correlation to RT doses (P < .0001). Specifically, doses up to 30 Gy appear to preserve sufficient vascularisation (~77% in comparison with control) and tissue architecture. By contrast, exposure to higher doses 40%-61% of the micro-vessels were lost.

CONCLUSION

Intensity-modulated radiotherapy doses above 30 Gy identified reduction in microvasculature which is a lower threshold than previously accepted. In pharyngeal cancer patients' doses to the jaw bones often exceed this threshold. Coupled with favourable survival in certain oropharyngeal and nasopharyngeal cancer, dental rehabilitation via implants provides a significant clinical challenge.

Hypofractionated intensity-modulated radiation therapy with concurrent cisplatin in locally advanced oropharyngeal cancer: feasibility experience from a Government cancer centre of Eastern India in a resource-constrained setting

Purpose:

Radiation therapy (RT), in combination with chemotherapy, is the mainstay in the treatment for locally advanced oropharyngeal cancer. We analysed the tumour response and the toxicity profiles in patients having locally advanced oropharyngeal cancers receiving hypofractionated intensity-modulated radiation therapy (IMRT) and concurrent chemotherapy with Cisplatin investigating the feasibility and radiobiological efficacy of the regimen, along with its use as a resource-sparing alternative for a high-volume centre.

Material and Methods:

The records of 41 eligible patients with locally advanced squamous cell carcinoma of oropharynx, registered from September 2015 to April 2017, treated with hypofractionated IMRT with concurrent Cisplatin, were analysed from the hospital database. Patients received concurrent chemo-radiation with 2 cycles of 3-weekly cisplatin on day 1 and day 22 along with hypofractionated IMRT, 55 Gy delivered in 20 fractions over 4 weeks. Patients were observed for any radiation reaction or chemotherapy toxicity at least once a week during the course of radiation therapy.

Results:

Twenty-nine patients (70·7%) achieved complete response and remaining 12 showed partial response. Acute grade 3 toxicity was observed mostly in the form of oral mucositis and radiation dermatitis. Both grade 3 oral mucositis and radiation dermatitis were seen in 15 patients (36·6%) and 7 patients (17%), respectively. The most common late toxicities were dysphagia and dry mouth. Twenty-five patients (61%) completed the overall treatment within 4 weeks’ duration.

Conclusion:

This hypofractionated regimen is feasible and was associated with tolerable acute and late morbidity and satisfactory locoregional response. Larger prospective, multi- institutional studies examining similar schedules may be undertaken to establish this as a standard practice, particularly for a high-volume centre.

Significance of overall concurrent chemoradiotherapy duration on survival outcomes of stage IIIB/C non-small-cell lung carcinoma patients: Analysis of 956 patients

Background

To investigate the detrimental effects of prolonged overall radiotherapy duration (ORTD) on survival outcomes of stage IIIB/C NSCLC patients treated with concurrent chemoradiotherapy (C-CRT)

Methods

The study cohort consisted of 956 patients who underwent C-CRT for stage IIIB/C NSCLC. Primary endpoint was the association between the ORTD and overall survival (OS) with locoregional progression-free survival (LRPFS) and PFS comprising the secondary endpoints. Receiver operating characteristic (ROC) curve analysis was utilized for accessibility of the cut-off that interacts with survival outcomes. Multivariate Cox model was utilized to identify the independent associates of survival outcomes.

Results

The ROC curve analysis exhibited significance at 49 days of ORTD cut-off that dichotomized patients into ORTD<50 versus ORTD≥50 days groups for OS [area under the curve (AUC): 82.8%; sensitivity: 81.1%; specificity: 74.8%], LRPFS (AUC: 91.9%; sensitivity: 90.6%; specificity: 76.3%), and PFS (AUC: 76.1%; sensitivity: 72.4%; specificity: 68.2%), respectively. Accordingly, ORTD≥50 days group had significantly shorter median OS (P<0.001), LRPFS (P<0.001), and PFS (P<0.001); and 10-year actuarial locoregional control (P<0.001) and distant metastases-free (P<0.011) rates than the ORTD<50 days group. The ORTD retained its significant association with survival outcomes at multivariate analyses independent of the other favorable covariates (p<0.001, for OS, LRPFS, and PFS): Stage IIIB disease (versus IIIC), lymph node bulk <2 cm (versus ≥2 cm), and 2–3 chemotherapy cycles (versus 1). The higher sensitivity for LRPFS (90.6%) than PFS (72.4%) on ROC curve analysis suggested the prolonged ORTD-induced decrements in locoregional control rates as the major cause of the poor survival outcomes.

Conclusions

Longer ORTD beyond ≥50 days was associated with significantly poorer OS, LRPFS and PFS outcomes, where reduced locoregional control rates appeared to be the main causative.

Comparison between hypo-fractionated dose-escalated volumetric modulated arc therapy and conventional concurrent chemo-radiation in locally advanced head and neck cancer: a pilot study

Objective:

In the treatment of locally advanced head and neck cancer (LA-HNC), both dose escalation and hypo-fractionation can improve tumour control rates with uncertain role of addition of concurrent chemotherapy. We aimed at developing a new radiotherapy protocol for patients not eligible to receive the standard concurrent chemo-radiation therapy (CCRT) with little toxicity profile.

Methods:

A total of 63 LA-HNC patients were randomised to receive either: 70 Gy in 35 fx in 7 weeks concurrently with cisplatin 100 mg/m2 every 3 weeks for 3 doses (Arm A) or 74 Gy in 33 fx in 6·5 weeks (Arm B). Volumetric modulated arc therapy plans were created for both treatment arms. We compared the local control (LC), progression-free survival (PFS), overall survival (OS) and acute and late toxicity between the two arms.

Results:

A total of 33 patients were in Arm A versus 30 patients in Arm B with median follow-up 24·2 months. No significant differences in LC, PFS and OS between the two arms. Complete remission occurred in 54·5 and 63·3% of patients in Arms A and B, respectively. All toxicities were significantly less in Arm B than Arm A.

Conclusion:

Slightly dose-escalated hypo-fractionated regimen is safe and feasible and has comparable efficacy and less acute and late side effects than conventional dose CCRT with avoidance of chemotherapy-related toxicities in LA-HNC patients.

Single-Arm Phase 2 Trial of Elective Nodal Dose Reduction for Patients With Locoregionally Advanced Squamous Cell Carcinoma of the Head and Neck

PURPOSE

To evaluate a novel chemoradiation therapy (CRT) regimen for patients with squamous cell carcinoma of the head and neck (SCCHN) incorporating a lower intensity modulated radiation therapy dose to electively treated neck lymph nodes than is currently standard.

METHODS AND MATERIALS

Eligible patients had locally advanced SCCHN of the oral cavity, oropharynx, larynx, or hypopharynx. The 7-week CRT course consisted of weekly cisplatin at 35 mg/m² concurrently with sequential-boost intensity modulated radiation therapy: 36 Gy to high- and low-risk planning target volumes followed by a sequential boost to the high-risk planning target volume to 70 Gy. The primary endpoint was elective nodal failure. Secondary endpoints were survival, toxicity, feeding tube duration, and quality of life evaluated by the FACT-HN and QOL-RTI surveys.

RESULTS

Between 2011 and 2014, 54 patients were enrolled, 31 (57%) of whom had human papillomavirus (HPV)-positive disease. Of the patients, 35 (65%) had stage IVa disease. The median follow-up period for survivors was 36 months (range, 12-66 months). Elective nodal failure did not develop in any patient. The actuarial 3-year survival rate for the entire cohort was 91% (95% confidence interval [CI] 0.79-0.96); for the HPV-negative group, 85% (95% CI 0.61-0.95); and for the HPV-positive group, 96% (95% CI 0.77-0.99). Common grade 3 toxicities were dysphagia (79%), mucositis and/or stomatitis (41%), nausea (20%), xerostomia (13%), vomiting (11%), and neutropenia (10%). The median feeding tube duration was 142 days. Patient FACT-HN scores were higher at 3, 6, and 12 months versus at the end of treatment (P < .0001). Total FACT-HN scores returned to pretreatment baseline by 6 months. Overall QOL-RTI scores were lower from pretreatment to the end of treatment through 12 months (P = .0001).

CONCLUSIONS

This CRT regimen for patients with advanced SCCHN demonstrated the potential feasibility of reducing the elective dose to the neck, a topic that requires additional study in future clinical trials.

An elective radiation dose of 46 Gy is feasible in nasopharyngeal carcinoma treated by intensity-modulated radiotherapy: A long-term follow-up result

The purpose of this study is to compare the treatment outcome of different radiation doses of elective neck irradiation (ENI) in nasopharyngeal carcinoma (NPC) patients treated with intensity-modulated radiotherapy (IMRT).In total, 504 patients with nondisseminated NPC who underwent magnetic resonance imaging before radical IMRT between 2000 and 2008 were retrospectively reviewed. The patients were classified into 2 groups based on the ENI dose: low ENI when the ENI dose was 46 Gy (n = 446) and high ENI when the ENI doses were 50 to 60 Gy (n = 58). All the patients in both the groups received a median dose of 72 Gy to the gross tumor and involved nodes. The fraction size was 2 Gy per fraction. Matching was performed between low ENI and high ENI in a 2:1 ratio, and the matching criteria were N-stage, T-stage, treatment modality, pathology classification, sex, and age.The median follow-up for all patients was 63.5 months. In all patients, the 5-year progression-free survival (PFS), local control (LC), regional control (RC), distant metastasis-free survival (DMFS), overall survival (OS), and cancer-specific survival (CSS) for low ENI and high ENI patients were 69.0% and 63.2% (P = 0.331), 89.0% and 83.9% (P = 0.235), 90.1% and 85.2% (P = 0.246), 86.8% and 76.6% (P = 0.056), 77.5% and 80.8% (P = 0.926), and 84.4% and 82.5% (P = 0.237), respectively. In the matched-pair analysis, the 5-year PFS, LC, RC, DMFS, OS, and CSS for matched low ENI and high ENI patients were 74.1% and 63.2% (P = 0.134), 92.0% and 83.9% (P = 0.152), 90.1% and 85.2% (P = 0.356), 86.2% and 76.6% (P = 0.125), 87.0% and 80.8% (P = 0.102), and 88.6% and 82.5% (P = 0.080), respectively. In the multivariable analysis for all patients, the ENI group was not a significant factor for PFS, LC, RC, DMFS, OS, and CSS.A low ENI dose of 46 Gy in 23 fractions is feasible in NPC patients treated with IMRT, and this concept should be validated in the prospective studies.

Challenges of Using High-Dose Fractionation Radiotherapy in Combination Therapy

Radiotherapy is crucial and substantially contributes to multimodal cancer treatment. The combination of conventional fractionation radiotherapy (CFRT) and systemic therapy has been established as the standard treatment for many cancer types. With advances in linear accelerators and image-guided techniques, high-dose fractionation radiotherapy (HFRT) is increasingly introduced in cancer centers. Clinicians are currently integrating HFRT into multimodality treatment. The shift from CFRT to HFRT reveals different effects on the tumor microenvironment and responses, particularly the immune response. Furthermore, the combination of HFRT and drugs yields different results in different types of tumors or using different treatment schemes. We have reviewed clinical trials and preclinical evidence on the combination of HFRT with drugs, such as chemotherapy, targeted therapy, and immune therapy. Notably, HFRT apparently enhances tumor cell killing and antigen presentation, thus providing opportunities and challenges in treating cancer.

Management of locally advanced HPV-related oropharyngeal squamous cell carcinoma: where are we?

HPV-related (HPV+) oropharyngeal cancer (OPC) has a better prognosis compared to HPV unrelated (HPV-) OPC. This review summarizes and discusses several of the controversies regarding the management of HPV+ OPC, including the mechanism of its treatment sensitivity, modern surgical techniques, chemotherapy regimens, and treatment de-intensification protocols. We also discuss and reconsider potential adverse prognostic factors such as tumor EGFR expression, tumor hypoxia, and patient smoking history, as well as the significance of retropharyngeal adenopathy. Finally, we discuss elective nodal treatment of uninvolved lymph node stations. While this review does not exhaust all controversies related to the management of HPV+ OPC, it aims to highlight some of the most clinically relevant ones.

Effect of radiotherapy delay in overall treatment time on local control and survival in head and neck cancer: Review of the literature

Treatment delays in completing radiotherapy (RT) for many neoplasms are a major problem affecting treatment outcome, as increasingly shown in the literature. Overall treatment time (OTT) could be a critical predictor of local tumor control and/or survival. In an attempt to establish a protocol for managing delays during RT, especially for heavily overloaded units, we have extensively reviewed the available literature on head and neck cancer. We confirmed a large deleterious effect of prolonged OTT on both local control and survival of these patients.

Patterns-of-failure after helical tomotherapy-based chemoradiotherapy for head and neck cancer: implications for CTV margin, elective nodal dose and bilateral parotid sparing

OBJECTIVES

There is debate about the optimal clinical target volume (CTV) expansion and prophylactic nodal dose (PND) in head and neck IMRT. We evaluated our patterns-of-failure (POF) after helical tomotherapy-based concurrent chemoradiotherapy (CCRT) to assess the oncologic safety of reducing the CTV, PND, and bilateral parotid sparing (BPS).

MATERIALS AND METHODS

All patients with locally advanced squamous cell carcinoma of the head and neck treated with curative intent CCRT between January 2007 and April 2013 at a single institution were included in this retrospective study. Locoregional recurrences (LRR) were overlaid on the treatment plan, and POF was determined relative to planned dose.

RESULTS

One hundred and fourteen patients treated with CCRT were evaluated, 74% of whom underwent BPS. The median follow-up for surviving patients was 29.3 months. The 3-year cumulative incidence of locoregional failure, distant metastasis, progression-free and overall survival were 20%, 20%, 56% and 73% respectively. The local failures (n = 12) were either entirely contained within or centered on the original gross tumor volume (GTV), and all but 2 regional recurrences were in GTV. There were no nodal failures in the low-dose or peri-parotid neck (including ipsilateral neck).

DISCUSSION

Nearly all LRR were located within the GTV suggesting that minimal-to-zero margin is required for CTV 70. The nodal recurrence pattern suggests the safety of routine bilateral parotid sparing and relatively low biologically equivalent dose (54 Gy in 33fx) to the low-risk neck.

A rationale for chemoradiation (vs radiotherapy) in salivary gland cancers? On behalf of the REFCOR (French rare head and neck cancer network)

BACKGROUND

Salivary gland carcinomas constitute a heterogeneous group of tumors, with over 20 histological subtypes of various prognoses. The mainstay of treatment is surgery, with radiotherapy advocated for unresectable disease or postoperatively in case of poor prognostic factors such as high grade, locally advanced and/or incompletely resected tumors. Concurrent chemotherapy is sometimes advocated in routine practice based on criteria extrapolated from squamous cell carcinomas of the head and neck, on radioresistance of salivary gland tumors and on results obtained in the metastatic setting. The aim of this review was to identify situations where chemotherapy is advocated.

MATERIAL AND METHODS

A search of literature was performed with the following key words: parotid, salivary gland, neoplasm, cancer, malignant tumor, chemoradiation, chemotherapy, radiotherapy and treatment. Case report and studies published before 2000 were not included.

RESULTS

Platinum-based regimens were the most frequent. Other regimens were reported and seemed dependent on histology. The level of evidence for the concurrent delivery of chemotherapy with radiation therapy is supported by a low level of evidence. Prescribing chemotherapy mostly relies on poor prognostic factors similar to those used to indicate high dose radiotherapy. Protocols vary with histology.

CONCLUSION

The rationale for adding chemotherapy to radiotherapy remains to be demonstrated prospectively. Although the type of systemic treatments used may be adapted on histology, the strongest rationale remains in favor of cisplatin.

Sensorineural Hearing Loss after Treatment for Head and Neck Cancer: A Review of the Literature

BACKGROUND

Definitive cisplatin-based chemoradiation is increasingly delivered as the treatment of choice for patients with head and neck cancer. Sensorineural hearing loss is a significant long-term side effect of cisplatin-based chemoradiation and is associated with potential major quality of life issues for patients. The purpose of this article was to review the mechanism behind sensorineural hearing loss in patients treated with cisplatin-based chemoradiation, including incidence, the contributions of radiotherapy and cisplatin to sensorineural hearing loss, and the impact of the toxicity on patient quality of life.

METHODS

Database searches were conducted through PubMed (National Centre for Biotechnology Information) and OvidSP Medline via the Queensland University of Technology Library website. General article searches were conducted through the online search engine Google Scholar. Articles were excluded if the full text was unavailable, they were not in English, or if they were published before 1990. Key words included hearing loss, ototoxicity, cancer, quality of life, cisplatin, and radiotherapy.

RESULTS/DISCUSSION

The total number of journal articles accessed was 290. Because of exclusion criteria, 129 articles were deemed appropriate for review. Findings indicated that sensorineural hearing loss is a significant, long-term complication for patients treated with cisplatin-based chemoradiation. Current literature recognizes the ototoxic effects of cisplatin and cranial irradiation as separate entities; however, the impact of combined modality therapy on sensorineural hearing loss is seldom reported. Multiple risk factors for hearing loss are described; however, there are contradictory opinions on incidence and severity and the exact radiation dose threshold responsible for inducing hearing loss in patients receiving combined modality therapy. Sensorineural hearing loss creates a subset of complexities for patients with head and neck cancer and these patients face significant quality of life impairment.

CONCLUSIONS

The literature review identified that sensorineural hearing loss is a major quality of life issue for patients treated with cisplatin-based chemoradiation for head and neck cancer. Further investigation evaluating the contribution of cisplatin-based chemoradiation to sensorineural hearing loss and the subsequent effect on patient quality of life is warranted.

Hypoxia-targeted radiotherapy dose painting for head and neck cancer using (18)F-FMISO PET: a biological modeling study

BACKGROUND

This study investigates the use of (18)F-fluoromisonidazole (FMISO) PET-guided radiotherapy dose painting for potentially overcoming the radioresistant effects of hypoxia in head and neck squamous cell carcinoma (HNSCC).

MATERIAL AND METHODS

The study cohort consisted of eight patients with HNSCC who were planned for definitive radiotherapy. Hypoxic subvolumes were automatically generated on pre-radiotherapy FMISO PET scans. Three radiotherapy plans were generated for each patient: a standard (STD) radiotherapy plan to a dose of 70 Gy, a uniform dose escalation (UDE) plan to the standard target volumes to a dose of 84 Gy, and a hypoxia dose-painted (HDP) plan with dose escalation only to the hypoxic subvolume to 84 Gy. Plans were compared based on tumor control probability (TCP), normal tissue complication probability (NTCP), and uncomplicated tumor control probability (UTCP).

RESULTS

The mean TCP increased from 73% with STD plans to 95% with the use of UDE plans (p < 0.001) and to 93% with HDP plans (p < 0.001). The mean parotid NTCP increased from 26% to 44% with the use of UDE plans (p = 0.003), and the mean mandible NTCP increased from 2% to 27% with the use of UDE plans (p = 0.001). There were no statistically significant differences between any of the NTCPs between the STD plans and HDP plans. The mean UTCP increased from 48% with STD plans to 66% with HDP plans (p = 0.016) and dropped to 37% with UDE plans (p = 0.138).

CONCLUSION

Hypoxia-targeted radiotherapy dose painting for head and neck cancer using FMISO PET is technically feasible, increases the TCP without increasing the NTCP, and increases the UTCP. This approach is superior to uniform dose escalation.

Radio-chemotherapy for bladder cancer: Contribution of chemotherapy on local control

The purpose of this study was to review the magnitude of contribution of chemotherapy (CT) in the local control of muscle invasive bladder carcinoma in the studies where a combined radio-chemotherapy (RCT) was used (how much higher local control rates are obtained with RCT compared to RT alone). Studies on radiotherapy (RT) and combined RCT, neo-adjuvant, concurrent, adjuvant or combinations, reported after 1990 were reviewed. The mean complete response (CR) rates were significantly higher for the RCT studies compared to RT-alone studies: 75.9% vs 64.4% (Wilcoxon rank-sum test, P = 0.001). Eleven of the included RCT studies involved 2-3 cycles of neo-adjuvant CT, in addition to concurrent RCT. The RCT studies included the one-phase type (where a full dose of RCT was given and then assessment of response and cystectomy for non-responders followed) and the two-phase types (where an assessment of response was undertaken after an initial RCT course, followed 6 wk later by a consolidation RCT for those patients with a CR). CR rates between the two subgroups of RCT studies were 79.6% (one phase) vs 71.6% (two-phase) (P = 0.015). The average achievable tumour control rates, with an acceptable rate of side effects have been around 70%, which may represent a plateau. Further increase in CR response rates demands for new chemotherapeutic agents, targeted therapies, or modified fractionation in various combinations. Quantification of RT and CT contribution to local control using radiobiological modelling in trial designs would enhance the potential for both improved outcomes and the estimation of the potential gain.

Can radiobiological parameters derived from squamous cell carcinoma of the head and neck be used to predict local control in anal cancer treated with chemoradiation?

OBJECTIVES

Parameters have been derived in head and neck cancer to account for the additional biological effective dose provided by synchronous chemotherapy. The purpose of this study was to establish whether such parameters could be used to predict local control differences in anal cancer.

METHODS

In anal cancer two randomised trials of radiotherapy vs chemoradiotherapy and two trials randomising between different synchronous chemotherapy regimens were identified. To predict differences in local control between the arms of the first two studies, a global value of 9.3 Gy for the chemotherapy biologically effective dose was employed. For the last two trials, values specific to differing chemotherapy schedules were derived. These values were added to the calculated biological effective dose for the radiotherapy component in order to predict local control outcomes in anal cancer trials.

RESULTS

The predicted difference in local control using the global value of 9.3 Gy for the addition of synchronous chemotherapy in the trials of radiotherapy vs radiotherapy and synchronous chemotherapy was 24.6% compared with the observed difference of 21.4%. Using schedule-specific values for the contribution of chemotherapy, the predicted differences in local control in the two trials of differing synchronous chemotherapy schedules were 7.2% and 12% compared with the observed 18% and 0%.

CONCLUSION

The methods initially proposed require modification to result in adequate prediction. If the decreased cisplatin dose intensity employed in anal cancer is modelled, more satisfactory predictions for such trials can be achieved.

ADVANCES IN KNOWLEDGE

This revised modelling may be hypothesis generating.

Can drugs enhance hypofractionated radiotherapy? A novel method of modeling radiosensitization using in vitro data

PURPOSE

Hypofractionated radiotherapy (hRT) is being explored for a number of malignancies. The potential benefit of giving concurrent chemotherapy with hRT is not known. We sought to predict the effects of combined modality treatments by using mathematical models derived from laboratory data.

METHODS AND MATERIALS

Data from 26 published clonogenic survival assays for cancer cell lines with and without the use of radiosensitizing chemotherapy were collected. The first three data points of the RT arm of each assay were used to derive parameters for the linear quadratic (LQ) model, the multitarget (MT) model, and the generalized linear quadratic (gLQ) model. For each assay and model, the difference between the predicted and observed surviving fractions at the highest tested RT dose was calculated. The gLQ model was fitted to all the data from each RT cell survival assay, and the biologically equivalent doses in 2-Gy fractions (EQD2s) of clinically relevant hRT regimens were calculated. The increase in cell kill conferred by the addition of chemotherapy was used to estimate the EQD2 of hRT along with a radiosensitizing agent. For comparison, this was repeated using conventionally fractionated RT regimens.

RESULTS

At a mean RT dose of 8.0 Gy, the average errors for the LQ, MT, and gLQ models were 1.63, 0.83, and 0.56 log units, respectively, favoring the gLQ model (p < 0.05). Radiosensitizing chemotherapy increased the EQD2 of hRT schedules by an average of 28% to 82%, depending on disease site. This increase was similar to the gains predicted for the addition of chemotherapy to conventionally fractionated RT.

CONCLUSIONS

Based on published in vitro assays, the gLQ equation is superior to the LQ and MT models in predicting cell kill at high doses of RT. Modeling exercises demonstrate that significant increases in biologically equivalent dose may be achieved with the addition of radiosensitizing agents to hRT. Clinical study of this approach is warranted.

Dosimetric impact of target definitions on normal structures in head and neck cancer

Background and Purpose

Previous work by our group suggests smaller target volumes may result in equivalent locoregional control for head and neck cancer. We evaluated whether smaller target volumes may also result in improved normal tissue sparing.

Methods and Materials

Ten patients with Stage III-IV head and neck cancer were contoured and planned according to target definitions in RTOG 0522 in a two dose level plan (RTOG), as well as a three dose level plan, using smaller target volumes and an intermediate dose prescription (3Dose). Plans were compared for coverage of targets and sparing of normal tissues

Results

The high dose target, elective nodal target, and total volume targeted were significantly smaller in 3Dose plans (p < 0.001). There was no difference in volume receiving 100% of each prescription level in RTOG or 3Dose plans. Mean dose to contralateral parotid, mandible, larynx, and inferior pharyngeal constrictor, and maximum dose to brainstem were significantly lower in 3Dose plans. There was no significant difference in maximum dose to spinal cord or volume of tissue not otherwise specified receiving 70 Gy.

Conclusions

Smaller target volumes with the addition of an intermediate dose volume results in improved sparing of most normal tissues.

Using fluorodeoxyglucose positron emission tomography to assess tumor volume during radiotherapy for non-small-cell lung cancer and its potential impact on adaptive dose escalation and normal tissue sparing

PURPOSE

To quantify changes in fluorodeoxyglucose (FDG)-avid tumor volume on positron emission tomography/computed tomography (PET/CT) during the course of radiation therapy and examine its potential use in adaptive radiotherapy for tumor dose escalation or normal tissue sparing in patients with non-small-cell lung cancer (NSCLC).

METHODS AND MATERIALS

As part of a pilot study, patients with Stage I-III NSCLC underwent FDG-PET/CT before radiotherapy (RT) and in mid-RT (after 40-50 Gy). Gross tumor volumes were contoured on CT and PET scans obtained before and during RT. Three-dimensional conformal RT plans were generated for each patient, first using only pretreatment CT scans. Mid-RT PET volumes were then used to design boost fields.

RESULTS

Fourteen patients with FDG-avid tumors were assessed. Two patients had a complete metabolic response, and 2 patients had slightly increased FDG uptake in the adjacent lung tissue. Mid-RT PET scans were useful in the 10 remaining patients. Mean decreases in CT and PET tumor volumes were 26% (range, +15% to -75%) and 44% (range, +10% to -100%), respectively. Designing boosts based on mid-RT PET allowed for a meaningful dose escalation of 30-102 Gy (mean, 58 Gy) or a reduction in normal tissue complication probability (NTCP) of 0.4-3% (mean, 2%) in 5 of 6 patients with smaller yet residual tumor volumes.

CONCLUSIONS

Tumor metabolic activity and volume can change significantly after 40-50 Gy of RT. Using mid-RT PET volumes, tumor dose can be significantly escalated or NTCP reduced. Clinical studies evaluating patient outcome after PET-based adaptive RT are ongoing.

Mucositis versus tumor control: the therapeutic index of adding chemotherapy to irradiation of head and neck cancer

PURPOSE

To determine whether the addition of concurrent chemotherapy to radiation for head and neck cancer (HNSCC) improves the therapeutic ratio regarding tumor control vs. mucositis.

METHODS AND MATERIALS

Data were taken from 14 randomized trials of radiation with or without concurrent chemotherapy for HNSCC. Mucositis-bioequivalent dose (mBED) was computed for each study using mBED = D [1 + d/(alpha/beta)] - 0.693(T - Tk)/Tp. An "S-value," relating the increase in the rate of Grade 3 (confluent) mucositis to the increase in mBED with radiation alone, was determined using data from trials of radiation alone with altered fractionation. We then determined the difference in the rate of mucositis and used the S-value to estimate the apparent difference in mBED in the chemoradiation and radiation alone arms for each trial. After accounting for differences in the radiation schedules, we estimated the mBED attributable to adding chemotherapy and compared it with previously published estimates of increases in tumor BED.

RESULTS

Computed S-values ranged from 0.4 to 1.7. For S = 1, the mean increase in mBED attributable to chemotherapy was 8.3 Gy(10) (SD = 6.4). The average difference between tumor-BED and mBED was 2.8 Gy(10) (SD = 6.0). Increasing the S-value decreases the estimated increase in mBED due to chemotherapy.

CONCLUSIONS

Concurrent chemotherapy improves the therapeutic index for radiation of HNSCC. Further refinements are needed in quantifying the therapeutic gain attributable to specific radiosensitizing agents in clinical trials, notably better and more consistent reporting of treatment sequelae.

Induction chemotherapy: to use or not to use? That is the question

The intensification of radiation, induction chemotherapy, and concomitant chemoradiotherapy has been extensively investigated over the past 2 decades for the nonsurgical management of locally advanced, nonmetastatic squamous cell head and neck cancer (HNC). Concurrent chemoradiation has emerged as the standard of care, with the majority of its benefit resulting from improvements in locoregional disease control. Distant failure has become a more prominent problem in conjunction with these improvements. Concurrent chemotherapy provides suboptimal adjuvant treatment for distant disease. Multiagent induction chemotherapy holds more promise especially with the use of taxane-based regimens. Induction chemotherapy followed by concurrent chemoradiation (sequential chemoradiation) is now under investigation. The rationale and evidence supporting the choice to use or not to use a sequential program are discussed.

Current state-of-the-art for concurrent chemoradiation

Throughout the last 2 decades, great strides have been made in managing patients with locally advanced head and neck squamous cell carcinoma. In many clinical settings, they translated to significant advances in treatment efficacy and improvements in disease prognosis. To achieve this, most strategies, ranging from induction to postoperative treatments, are essentially based on multidisciplinary approaches. Nowadays, the indication and sequencing of surgery, radiotherapy, and systemic treatments are carefully weighted in the function of risk levels, efficacy results, and quality of life. Along this track, the coadministration of chemotherapy and radiotherapy was shown, as definitive or adjuvant treatment, to improve the results of conventional radiotherapy alone. However, recent prospective trials showed that the compliance of patients to aggressive approaches is more of a concern for poor tolerability and reduced compliance inevitably impact on treatment dose intensity, leading to the delivery of suboptimal regimens. Therefore, further efforts to tailor novel, multidisciplinary approaches based on drug-radiation interactions have been put forth to optimize treatment outcomes in terms of both disease control and quality of life. Because therapy is becoming more intense, a careful recording and reporting of treatment-related morbidity is also a crucial element in estimating the therapeutic gain from competing strategies.

Use of concept of chemotherapy-equivalent biologically effective dose to provide quantitative evaluation of contribution of chemotherapy to local tumor control in chemoradiotherapy cervical cancer trials

PURPOSE

To express the magnitude of the contribution of chemotherapy to local tumor control in chemoradiotherapy cervical cancer trials in terms of the concept of the biologically effective dose.

METHODS AND MATERIALS

The local control rates of both arms of each study (radiotherapy vs. radiotherapy plus chemotherapy) reported from randomized controlled trials of concurrent chemoradiotherapy for cervical cancer were reviewed and expressed using the Poisson model for tumor control probability (TCP) as TCP = exp(-exp E), where E is the logarithm of cell kill. By combining the two TCP values from each study, we calculated the chemotherapy-related log cell kill as Ec = ln[(lnTCP(Radiotherapy))/(lnTCP(Chemoradiotherapy))]. Assuming a range of radiosensitivities (alpha = 0.1-0.5 Gy(-1)) and taking the calculated log cell kill, we calculated the chemotherapy-BED, and using the linear quadratic model, the number of 2-Gy fractions corresponding to each BED. The effect of a range of tumor volumes and radiosensitivities (alpha Gy(-1)) on the TCP was also explored.

RESULTS

The chemotherapy-equivalent number of 2-Gy fractions range was 0.2-4 and was greater in tumors with lower radiosensitivity. In those tumors with intermediate radiosensitivity (alpha = 0.3 Gy(-1)), the equivalent number of 2-Gy fractions was 0.6-1.3, corresponding to 120-260 cGy of extra dose. The opportunities for clinically detectable improvement are only available in tumors with intermediate radiosensitivity with alpha = 0.22-0.28 Gy(-1). The dependence of TCP on the tumor volume decreases as the radiosensitivity increases.

CONCLUSION

The results of our study have shown that the contribution of chemotherapy to the TCP in cervical cancer is expected to be clinically detectable in larger and less-radiosensitive tumors.

Correction to Kasibhatla et al. How much radiation is the chemotherapy worth in advanced head and neck cancer? (Int j radiat oncol biol phys 2007;68:1491-1495)

PURPOSE

To correct several elementary radiobiologic errors in the otherwise admirable article by Kasibhatla, Kirkpatrick, and Brizel (2007) on estimating the equivalent radiation effect of the concomitant chemotherapy in head-and-neck chemoradiotherapy.

METHODS AND MATERIALS

(1) Their equation was wrong because it omitted the lag or onset time of repopulation in tumors, Tk. Instead of zero days this should be 18-35 days. (2) Instead of a doubling time of 5 days, at most 3 days should be used for head-and-neck tumors. (3) Their slope "S" (the gamma-50 slope) for head-and-neck tumors should be 1.7, not 1.1. The same percentages of increased locoregional control as quoted by Kasibhatla et al. are used.

RESULTS

The average time-corrected biologically effective dose for the 16 schedules listed should be 72.4 instead of 63.1 Gy(10). The average gains in locoregional tumor control are the equivalent of 8.8 Gy(10), not 10.6 Gy(10) (p = 0.05).

CONCLUSIONS

The equivalent number of 2-Gy fractions of concomitant chemotherapy as used in the 16 listed schedules is 3.6 (95% confidence interval, 2.7-4.1), not 5 as claimed by Kasibhatla et al. The difference is statistically significant (p < 0.001).

Patterns of locoregional failure after exclusive IMRT for oropharyngeal carcinoma

PURPOSE

To assess the patterns of failure after intensity-modulated radiotherapy (IMRT) for oropharyngeal squamous cell carcinoma (SCC).

METHODS AND MATERIALS

We analyzed patients treated at the University of Texas Medical Branch between May 2002 and February 2006 who met the following criteria: (1) definitive IMRT without chemotherapy for oropharyngeal SCC; (2) no pretreatment radical surgery; (3) minimal follow-up of 1 year. The location of each nodal/primary failure was co-registered to the pretreatment planning computed tomography scan and then expanded by 5 mm to a planning target volume (PTV) of the failure (PTV-f). We then investigated whether the prescription dose to the PTV-f had been appropriate for the amount of disease present before treatment and whether the PTV-f had been adequately covered.

RESULTS

A total of 50 patients were eligible. With a median follow-up of 32.6 months (range, 12.1-58.6), three local and six regional failures were observed in 8 patients. All but one failure, that had been neglected, were recorded within 14 months of the treatment end. Of the nine failures, four developed in the neck treated electively to the lowest dose level; in all of them, we could retrospectively identify initial positive lymph nodes that might have justified the subsequent failure. The remaining five failures developed in proximity of the high-dose volume. In all but one, the volume of region of interest receiving >/=95% of the dose of the PTV-f was >95%, suggesting adequate coverage. In 1 patient, about 20% of PTV-f was outside the 95% isodose, so that marginal underdosing could not be ruled out.

CONCLUSIONS

A potential cause could be identified in all the failures in the lowest dose level. The implications and possible remedies are discussed. Most failures around the high-dose region were "true failures" with no apparent technical cause.

concomitant chemoradiotherapy with mitomycin C and cisplatin in advanced unresectable carcinoma of the head and neck: phase I-II clinical study

PURPOSE

To evaluate the toxicity and efficacy of concomitant chemoradiotherapy with mitomycin C and cisplatin in the treatment of advanced unresectable squamous cell carcinoma of the head and neck.

PATIENTS AND METHODS

Treatment consisted of conventional radiotherapy (70 Gy in 35 fractions), mitomycin C 15 mg/m(2) IV, applied after the delivery of 10 Gy, and cisplatin at an initial dose of 10 mg/m(2)/d IV, applied during the last 10 fractions of irradiation ("chemoboost"). The cisplatin dose was escalated with respect to the toxic side effects by 2 mg/m(2)/d up to the maximum tolerated dose (MTD) or at the most 14 mg/m(2)/d (Phase I study), which was tested in the subsequent Phase II study.

RESULTS

All 36 patients had Stage T4 and/or N3 disease, and the majority had oropharyngeal (50%) or hypopharyngeal (39%) primary tumors. Six patients were treated at each of the three cisplatin dose levels tested (Phase I study). Dose-limiting toxicity was not reached even at 14 mg/m(2)/d of cisplatin, which was determined as the MTD and tested in an additional 18 patients (Phase II study). After a median follow-up time of 48 months, 4-year locoregional control, failure-free, and overall survival rates were 30%, 14%, and 20%, respectively. In 24 patients treated at the cisplatin dose level of 14 mg/m(2)/d, the corresponding rates were 40%, 20%, and 22%, respectively.

CONCLUSION

Concomitant chemoradiotherapy with mitomycin C and cisplatin "chemoboost" at 14 mg/m(2)/d is feasible, with encouraging survival results if the extremely poor disease profile of the treated patients is considered.